Two-cycle engine with slot scavenging and airless fuel injection



WP RIEHM Nov. 11,1930,

TWO-CYCLE ENGINE WI TH SLOT SCAVENGING AND AIRLESS FUEL INJECTION FiledFeb. 4. 1929 2 She ets-Sheet 1 Patented Nov. 11,- 1930- UNITED STAWILHELM RIEHM', or AUGSBURG, GERMANY, AssiqnoR T MASOHINENFABRIK AUGS-BURG-NURNBERG A. e., or AUGSBURG, GERMANY, A CORPORATION 01 GERMANYTWO-CYCLE ENGINE wxrn SLOT scAvENeING m nrnnnss FUEL InJE 'rIoNApplication filed February 4, 1929, Serial No.

This invention relatesto internal combustion engines and moreparticularly to-.two cycle engines. v 1

One of the principal objects of the inven-- stion is the provision ofatwo 'cycle engine operating with airless fuel injection, and havingscavenging air and exhaust ports or slots controlled by the piston,meansbeing provided to create a whirling action of the fluid in thecombustion chamber substantially at or after the start of thecompression stroke. Another object of the invention resides in themethod of-operation'of such an engine.

Other objects andadvantages of the inven-. tion will be apparent fromthe following-description and the accompanying drawing.

In the drawing, in which like characters of reference designate likeparts throughout. the several views thereof,-

Fig. 1 is a longitudinal section through one end of a cylinder embodyingthepresent in-- vention;

Fig. 2 is-a transverse section taken at right angles to the cylinderaxis along the line AB of Fig. 1;

Fig. 3 is a section on Fig.1;and I I 'Fig. 4 is a diagram showing'thesequence of operations.

the line O -D 'of 'This invention is preferably'employed inl v 1s 1norder to prevent a dlrect flow of a1 between the slots d anda.

connection with a double acting twostroke engine adapted to operate withairless fuel injectionfand is so illustrated in the draw-'.. ingas oneembodiment thereof, although obviously-the invention is not to, be.limited to engines of the doubleacting type.

For purposes of easier understanding, the drawing is'somewhatdiagrammatic in form and only so much of the engine is illus trated asis needed for a clear disclosure of the invention. As shown,-the enginecylinder a contains two rows of ports. or slots b and c, the ports I),being the scavenging ports, are arranged closer tothe' center of thecylinder than the exhaust 'or'outlet portsc. The entering scavengingstream of air flows in accordance with the arrow shown, when the ports 6and c are opened by the piston which controls them, t eseports beingpreferably arranged on one side of the cylin- 337,255, and in GermanyFebruary 17, 1928.

der in adjacent planes so that the scavenging:

air flows across the cylinder along the cylinder and then back along thecylinder after reversing itself at the cylinder end, then flowing out ofthe exhaust slots 0, .thus effectively scavenging the-burnt gas from theTss PATENT OFFICE d are provided in the cylinder Wall, preferablyopposite the slots b and c. The supplementary slotsd, like the. slots 6and 0, are adapted'tobe closed'oi' controlled by the piston, the slots(Z being preferably arranged in the same transverse plane as the exhaust.slots 0. A supplementary flow of fluid may pass into the combustionspace throughthese slots 11, this fluid being air. As seen from Fig. 2the slots 03 are arranged so that the air entering the cylinder isdirected'substantially tangentially so as to set .thefluid in thecylinder into a rotative whirl, and as shown in Fig.1, the passage 6through-which the supplementary flow of air passes to the slots (1, isinclined upwardly towards theend of the cylinder so that the. flow ofair entering' the cylinder through the ports 03 is-directed at an angleto the .cylinder axis. This In order to avoid aloss of scavenging airand prevent the scavenging air entering through the slots 6 fromimmediately escap- -f ing-through the opposite slots d a suitable knownmanner in accordance with the engine operation so as to maintain thepassage e closed except" when thedesired supplementary air flow throughthe slots or.p0rts zlshouldtake place. This valve opens substantially atthe time the compression stroke starts, and just after the piston hasclosed the scavenging air ports I), asindicated at the point 5,in Fig.4. The valve f' controlling theflow of supplementary air through theports (Z maintains thispassage closed so long as the scavenging airslots. 12 are open,

but as" so 'on' as the scavenging air slots are closed, as apparentfrom. Fig. 4 of the draw- 3 and that chang comprisin 03, while movingwithoutdepartmg from the scope of the inclaims.- I

,Whatis claimedisrslots dgand a, as indicated .at the point 4. The valvelifting curve is shown in section in Fig. 4 as extending from the oint.3 to the point 5. The valve 7 is close after the end of thepiston passesby the ports 0 and towards the head of the cylinder, and t e valve 7remains closed during the uncovering of the slots 0 and d on the workingor "expansion stroke of the a piston. The time of opening of the exhaustslot 0 and the supplementary slot d-is indicated at point 1, while 2'indicates the time of opening of the scavenging slot 6. .U. T. indicatesthe lower dead centerposition and O. T. indicates the upper. dead centerposition of the iston:

.Any suita le means ma be rovided, forcausing a supplementary ow 0 airthrough the slots (1 when the passage e is opened y the valve('{, and.as this supplementary flow of air is irectedsubstantially tangentially,the contents of the c linder have a whirling motion im arted to them andarethus caused to move a outthe axis of the cylinder while the pistonmoves up towards the head of the I cylinder and compresses the contents.The compressed contents of the cylinder are thus whirling when the fuelis introduced through the fuel injection nozzle 9 shown in the cylinderhead, and thus an even distribution ofv the fuel is obtained.

. While the method herein described, and

the formof apparatus for carrying this method into effect, constitutepreferred em- .bodiments of the invention, it is to be 'under-.

stood that the invention is not limited to this precise method and formof apparatus, es may bemade ineither vention which is defined in theappended 1. A we cycle engine of the class described,

a cylinder having an exhaust port, a s avenging air inlet port adjacent,said exhaust port, anda piston reciprocable within said'cylinder tocontrolflsaid orts, said ports being arranged on the cylinder so as tocause a flow of scavenging air across, 'along, and back along thecombustion space, 3 a supplementary port in the cylinder wall at adistance from said'exhaus't and inlet ports and arranged angularly.with. respect a to radial directions-for admitting fluid rdtativelytothe combustion space substantially-at the start of the compressionstroke to impart a whirling motion to the fluid in the cylinder.

2. A' two cycle engine of the class described operating with airlessfuel injection,

comprising acylinder having an exhaust port, ascavengingair inlet port,and a piston vfluid in the cylinder, sai

ports,- said supplementary ports ranged so that'the air flowstherethrough in a entially direction and in- 'said ports-,sa'idvcylinder atone side thereof in adjacent parallel planes .so as to causea flow of scavenging ai'r across, along, and back along the com- 70bustion space, and a supplementary port in the cylinder wall arrangedangularly with from said, inlet and exhaust 'ports or .admitting fluidrotatively to the combustion space to impart a whirlin supplementaryport being positioned at such a location in the cylinder wall as to becontrolled by the piston substantially simultaneously with the controlof said exhaust port, and a valve for controlling the flow through saidsupplementary port and mechanism for operating said valve to open itafter the piston has uncovered the said inlet ports.

'3. A two cycle engine of. the class derespect to radial directions andat a 'd'stance motion to the scribed, operating .with'airless fuelinjection,

. comprising a'cylmder having exhaust ports,

scavenging air inlet orts, and a piston re ciprocable within'said'cylinder to control said ports, said ports being arranged on oneside of the c linder to provide for reversed scavenging ow, andsupplementary air inlet ports independent of said scavenging air inletports provided in said cylinder opposite said scavenging and exhaustports and ada ed to be closed by said-pismn substantia 1y concu r rentlywith the closing of said exhaust Y ports, said supplementary ports beingarran edatan angle to the radial directions so tf'at the air flowstherethrou'gh in a substantially tangentially direction to .set thefluid in the cylinder into a rotative whirl.

4. A two cycle en ine I of the class described, operating wit airlessfuel injection,

comprising a cyllnder having exhaust ports,

. scavenging air inlet ports; and a piston reciprocable within saidcylinder to. control said ports being arranged on one c linder toprovide for reversed said ports, side of the scavenging ow,andsupplementary air in let'ports independent of said scavenging airinlet ports provided in said cylinder opposite said scavengin andexhaust ports and ada ted to be close by said pistonsubstantiallyconcurrently with the closing. of said exhaust being arscribed,operating with airless fuel injection,

. comprising 'acyhnder having exhaust ports,

scavenging air inletorts," and a piston reside of the cy scavengingflow,

and supplementary air inlet lot 5. A two cycle. engine of the class de-I ciprocable withinfs'ard'cylinder' to control 1 ports bemg arranged, onone" der to prov1de for reversed ports independent of said scavengingair inlet ports provided in said cylinder opposite a substantiallytangentially direction to set the fluid in the cylinder into'a rotativewhirl,

and a valve for. co'ntrollin' the flow of supplementary air through saldsupplementary ports and adapted to open substantially at the time ofclosing of the scavenging air inlet ports.

L In testimon; whereof I have aflixed my signature.

WILHELM RIEHM.

with the closing of said

